good point and sorry for taking up this thread space with this nonsense bickering.
the bulk of my noise seems to be coming from both the tranny area and the rear diff. again, the only reason why i'm concerned with the rear diff noise is because i saw the pic that was posted of the scored rear diff housing.
as stated by PORTER, this groaning sound could be attributed to the difference in rolling tire diameters (a function of tire air pressures). btw, point well taken PORTER.
one of the previous posted comments stated that the dealer said that the noise was "a drivetrain alignment problem". i took "alignment problem" as meaning cocked prop shaft or something to that nature. this is what threw me from understanding how/why the dealer felt adjusting the tire pressure to an 8 psi delta would help. now i understand what porter was referring to.